Mobile transformer apparatus



March 3, 1964 s. H. WlLK ETAL MOBILE TRANSFORMER APPARATUS 5 Sheets-Sheet 1 Filed Dec. 7, 1959 March 3, 1964 s. H. WlLK ETAL 3, ,73

MOBILE TRANSFORMER APPARATUS Filed Dec. 7, 1959 3 Sheets-Sheet 2 March 3, 1964 s. H. WlLK ETAL 3,123,783

MOBILE TRANSFORMER APPARATUS Filed Dec. 7, 1959 v s Sheets-Sheet 3 United States Patent 3,123,73 TRANSFGRh/iF-JR APPARATUS gtanley H. Wills John A. Addy, Pittslield, Mass,

designers to General Electric Company, a corporation of New York Filed Dec. 7, 195d, Ser. No. 857,758 ll Claim. (63336-55) This invention relates to electrical apparatus, and more particularly to an improved fluid expansion system for such apparatus.

Many types of electrical apparatus, and in particular transformers, are immersed in a sealed tank containing an insulating and cooling fluid, such as transformer oil or a dielectric gas. In this type of system it has proved advantageous to employ fluid expansion reservoirs of the type which provide-a chamber connected to the fluidfllled tankhousing the electrical apparatus. The chamber is partially filled with the same type of fluid, and may contain aflexible diaphragm or bag vented to the atmosphere. When the fluid in the tank expands or contracts due to temperature changes, fluid flows to or from the reservoir, and expansion or contraction is absorbed by the flexible'diaphragm or bag. For additional details, reference maybe made to page 59 of the September 9, 1957 edition of Electrical World where such a system is illustrated and described in greater detail. Reservoirs of the conservator type in which no flexible members is used and the fluid is in contact with air have also been employed.

In fluid systems of the type described above, the pressure in the tank enclosing the apparatus should always be positive (i.e., greater than atmospheric) so that if a leak occurs in the system, the fluid-will flow out of the tank and reveal the leak. Also, with a positive pressure on the system, no air or moisture will leak into the system and decrease the dielectric strength of the insulating fluid. Consequently, it has been the practice in the past to mount the reservoir on top of the tank containing the electrical apparatus. In this way a fluid head is established, and the pressure in the tank is always greater than atmospheric pressure.

The mounting of the reservoir on top of the tank necessarily increases the height of the apparatus. In many types of electrical apparatus, and in particular in large types of power transformers, severe design limitations are placed on the apparatus by the maximum height that can be tolerated. This problem is particularly acute in mobile transformers. This type of apparatus is mounted on the bed of a vehicular frame and moved from place to place on public highways to replace transformers that must be repaired or temporarily taken out of operation. Severe limitations are encountered in the construction of mobile apparatus because of the legal limitations placed on the heights of vehicles that are allowed on public highways and also because of the heights of tunnels and bridges and other obstructions under which or through which the apparatus must pass. Consequently, we have chosen an embodiment of this type of apparatus as an illustration of how our invention can be practiced.

Accordingly, it is an object of our invention to provide an electrical apparatus, such as a transformer, having a fluid reservoir applied thereto, in which the reservoir can be raised or lowered in accordance with height restrictions placed on the apparatus.

it is another object of our invention to provide a fluid system for electrical apparatus in which an expansion chamber in the fluid system may be raised or lowered.

It is a further object of our invention to provide a method of acquiring road clearance for electrical apparatus.

Patented Mar. 3, 19554:

Briefly stated, according to one aspect of our invention, We provide a transformer in which a fluid reservoir is connected to the interior of a tank enclosing the transformer. The reservoir can be raised or lowered according to the height restrictions that are placed on a mobile vehicle upon which the transformer may be mounted.

While the specification concludes with claim particularly pointing out distinctly claiming the subject matter which we regard as our invention, it is believed that the invention will be better understood from the following description taken in connection with the accompanying drawings.

in the. drawings:

FEGURE 1 is a side elevation of av mobile transformer unit employing our invention.

FEGURE 2 is an isometric view of a portion of the apparatus illustrated in FIGURE 1, showing the fluid reservoir in raised position.

FIGURE 3 is a side elevation, partially cross-sectional, view of the apparatus shown in FIGURE 2 with the reservoir in lowered position.

FIGURE 4 is'a partially cross-sectional view of the apparatus shown in FIGURE 2 taken along the line 44.

Referring now to the drawings, and more in particular to FTGURE l, therein is illustrated a mobile transformer l of the type which is mounted on a vehicular frame 2 and adapted to be towed'by motive means, such as the automobile 3. The transformer assembly It? comprises an enclosure tank ll. in which is mounted a conventional transf rmer T2 '(indicated'in phantom). The tank ill is filled with an insulating fluid, such as transformer oil 13, and may have the conventional accessories attached thereto, such as coolers M, bushings 15, etc. in order to provide for expansion of the fluid 13 in the tank 11, a reservoir 2d may be applied to the mobile transformer 1. Because mobile vehicles which pass over public highways are restricted in height, the reservoir 2% is movably mounted on the tank 11 in order that it can be raised or lowered so as to decrease the over-all height of the apparatus.

Referring now to FIGURES 24, the reservoir 2t) is shown in greater detail. The reservoir Ell may comprise an expansion chamber 21 in which an inflatable bag 22 is vented to the atmosphere by means of a port 23. The interior of the chamber 21 may be connected to the interior of the tank ill at the upper end thereof by means of a flexible fluid conduit 24. Thus, when the expansion chamber flil is in the raised position shown in FIGURES 2 and 4, the fluid in the tank ll. will be under pressure greater than atmospheric pressure because of the fluid head caused by the fluid in the tank 21 being above that in the tank ll. When temperature changes cause'the fluid in the tank llll to-expand or contract, fluid will move backand forth through-the conduit 24, and the expansion or contraction will be absorbed by the bag 22, which will expand or contract a similar amount. The reservoir Ell may be provided with means 25' for indicating the fiuid level. Although the above described fluid expansion system is thepreferred embodiment of our invention that produces the most satisfactory results, it is also contemplated that a reservoir employing a flexible diaphragm in place of the bag 22, or a mere fluid conservator in which the fluid is in contact with air may also be used Without departing from the spirit of our invention.

The expansion chamber 21 may be movably mounted for raising and lowering by suitable means such as pairs of supports El and 32 (see FIGURE 2). The supports 31 and 32 are pivoted at one end to the upper surface of the tank 11 and pivoted at their other end to a side of the expansion chamber 211. Means may be provided for aresas supplying a force for moving the expansion chamber 21 to its raised position. For example, a hydraulic piston and cylinder assembly 40 connected by means of a fluid conduit 41 to a hand-operable pump 42 may be provided beneath the chamber 21. Thus, when it is desired to raise or lower the chamber 21, the operator of the mobile unit need only crank the handle on the pump 42 and supply pressure to the hydraulic assembly 40 to raise the chamber 21. Stop means 50 connected to the tank 11 may be provided beneath the chamber 21 to support the chamber when it is in its lowered position. As illustrated in FIG- URE 3, a cross beam 33 rests on the stop means 51), and the chamber 21 rests on the supports 32. The stop means 50 may be connected to the tank 11 by suitable means such as the cantilevers 51.

A strut assembly 60 may also be applied to the expansion chamber 21 for supporting the chamber in its raised position. The strut assembly 60 comprises pairs of locking elements or links 61 and 62, the upper links 61 being pivotally attached to locking pin 63 adjacent the bottom of the chamber 21. The lower links 62 may be pivotally attached at 64 to the support means 50. The links 62 may be provided with elongated apertures 65 in which a pin 66 connecting the links 61 is movable. One end of the links 62 may have notches 67 therein for receiving the pin 63. Thus, when the expansion chamber 21 has been raised above the upper surface of the tank 11 (see FIGURE 4) by means of the hydraulic assembly 40, the links 61 will be carried beyond the links 62 so that the pin 63 is above the notches 67. When the links 61 and 62 are aligned in the latter positions, some of the pressure in the assembly 40 may be released, thus lowering the expansion chamber 21 slightly and allowing the locking pin 63 to come to rest in the slots 67. This mechanism thus provides vertical support for the chamber 21, and after the pin 63 has been locked in place in the notches 67, pressure in the assembly 40 may be released. Thus, the expansion chamber 21 need not be supported only by the hydraulic assembly 40 and may be maintained in raised position even if the hydraulic assembly develops a leak.

When it is desired to lower the chamber 21, the operator of the vehicle need merely crank the handle on the pump 42 and thus provide pressure in the assembly 40 which will raise the chamber 21 so that the pin 63 becomes disengaged from the notch 67. The above described apparatus provides a safety feature in that before the chamber 21 can be lowered, the links 61 and 62 must be manually and purposely pivoted apart in order to perrnit lowering of the chamber 21.

The above described strut assembly 60 is the preferred embodiment of our invention that possesses the advantages of having a minimum of parts that can wear out or become broken and of positively locking to support the reservoir 20. However, it is contemplated that other supporting structures, though not as desirable as that illustrated, may be employed without departing from the true spirit and scope of the invention, as defined in the appended claim. For example, toggle links that move to an over center rest position may also be employed in place of the assembly illustrated.

It has thus been shown that we have provided an apparatus in which the advantages achieved in expansion chamber type fluid reservoirs are achieved without the 4 disadvantages inherent in a structure that must be mounted on the top of an apparatus tank that undesirably increases height or" the apparatus. We have achieved these advantages by providing a fluid reservoir which is movable to selected positions above or below the upper surface of the tank, thus permitting the reservoir to be above the ank when the apparatus is in operation, yet permitting lowering of the reservoir to below the upper surface of the tank and reducing the height of the apparatus when it must be transported on public highways. Consequently, our invention also provides a unique method of acquiring road clearance for electrical apparatus.

it will be understood, of course, that while the form of the invention herein shown and described constitutes the preferred embodiment thereof, it is not intended herein to illustrate all of the possible equivalent forms or ramifications thereof. It will also be understood that the words used are Words of description rather than of limitation, and that various changes may be made without departing from the spirit or scope of the invention herein disclosed, and it is aimed in the appended claim to cover all such changes that fall within the true spirit and scope of the invention.

What we claim as new and desire to secure by Letters Eatent of the United States is:

A mobile transformer comprising a winding and core assembly supported by a vehicular frame, said assembly being enclosed in a fluid filled tank, a fluid reservoir movably mounted on said tank, said reservoir comprising an expansion chamber having a flexible bag therein, said bag having its inside vented to the atmosphere through an aperture in said chamber, a fluid conduit hydraulically connecting fluid in said reservoir in contact with the outside or" said bag to the inside of said tank adjacent the upper surface of said tank, at least one pivotable support connecting one side of said reservoir to the upper surface of said tank, at least one other pivotable support connecting the under side of said reservoir to a side of said tank, stop means on said tank for supporting said reservoir in its lowered position, hydraulic means for raising said reservoir, and a strut assembly on said tank for supportin said reservoir in its raised position, said strut assembly comprising an upper link and a lower link, said upper link being pivotally attached to said chamber by means of a locking pin, and said lower link being pivotally attached to said stop means, there being an elongated slot in one of said links, a pin in the other of said links movable in said slot, said lower link having a notch in the upper end thereof, and said locking pin being received by said notch when said reservoir is in its raised position.

References (Iited i the file of this patent UNITED STATES PATENTS 1,230,315 Nash June 19, 1917 1,508,201 Treanor Sept. 9, 1924 2,201,189 v Makaroif May 21, 1940 2,427,184 Bilodeau Sept. 9, 1947 2,512,150 Geren June 20, 1950 2,674,386 Larson Apr. 6, 1954 2,683,545 Wood July 13, 1954 OTHER REFERENCES Electrical World, p. 59, Sept. 9, 1957. 

